2. www.strath.ac.uk/spacespace@strath.ac.uk Synergistic Approach of Asteroid Exploitation and Planetary Protection From Threat to Action 9-12 May 2011 Joan-Pau Sanchez 2011 IAA Planetary Defense Conference

3. Use an arrow like this to mark current section Introduction  Possible synergies between space systems capable of deflecting realistic impact threat and, at the same time, gravitationally capturing small asteroids for later resource exploitation. Low-thrust tugboat model as a space system. Tugboat system attaches to the asteroid surface and provides continuous thrust. 1.Assessment on the capability of such a system to deflect realistic impact threats. 2.Statistical population that could be manoeuvre into Earth-bound orbits. Introduction Deflection: 1. Procedure 2. Impactors 3. Protection Asteroid Capture 9-12 May 2011 2Joan Pau Sanchez Source: ESA

4. Use an arrow like this to mark current section Deflection: Procedure Introduction Deflection: 1. Procedure 2. Impactors 3. Protection Asteroid Capture 9-12 May 2011 3Joan Pau Sanchez Earth orbit NEO orbit Rendezvous Trajectory  17,518 impactors. Deflection Action 1. Baseline Design 5,000 kg wet mass v ∞ of 2.5 km/s Medium-to-large mission  The objective is to compute the mass of the largest object that the tugboat system could deflect from each one of the impacting orbits.

5. Use an arrow like this to mark current section Deflection: Set of Virtual Impactors Introduction Deflection: 1. Procedure 2. Impactors 3. Protection Asteroid Capture 9-12 May 2011 4Joan Pau Sanchez Set of virtual impactors plotted as dots of size and colour as a function of the relative frequency that should be expected for each impactor. =1% =0.2% =0.05% =0.01% ≤ 0.005%  Complete set of weighted impactors:

6. Use an arrow like this to mark current section Deflection: Planetary Protection Introduction Deflection: 1. Procedure 2. Impactors 3. Protection Asteroid Capture 9-12 May 2011 5Joan Pau Sanchez Type of Event Approximate range of Impact Energies (MT) Approximate Range Size of Impactor Airburst1 to 10 MT15 to 75 m Local Scale10 to 100 MT30 to 170 m Regional Scale100 to 1,000 MT70 to 360 m Continental Scale1,000 MT to 20,000 MT150 m to 1 km Global20,000 MT to 10,000,000 MT400 m to 8 km Mass ExtinctionAbove 10,000,000 MT>3.5 km Table 1: Impact hazard categories Type of EventLead Time 1 year2.5 years5 Years10 Years20 years Airburst51%93%99%100% Local Damage0.01%1.6%18%78%98% Regional D.0% 6% Continental D.0% Global D.0% Table 2: Levels of Planetary Protection

7. Use an arrow like this to mark current section Asteroid Capture Concept 9-12 May 2011 6Joan Pau Sanchez  On the possibility of moving small near Earth asteroids and inserting them onto Earth bound trajectories for later utilization. How much material could a 5000 kg low thrust spacecraft transport back to Earth?  Low Thrust is a very limiting constraint. The final Earth orbit insertion needs to be ballistic or unaided by the propulsion system.  Ballistic capture may be possible for objects with relative velocities v ∞ below 1 km/s.  Grazing aero-assisted trajectories may be possible to capture objects with relative velocities v ∞ above 1 km/s. Only aero-braking trajectories are designed so that maximum dynamical pressure does not exceed material Strength. Introduction Deflection: 1. Procedure 2. Impactors 3. Protection Asteroid Capture

8. Use an arrow like this to mark current section Asteroid Capture Concept Type of Capture Lead Time 1 year2.5 years5 Years10 Years20 years Ballistic >60t (12) >105t (21) >220t (44) >385t (77) >590t (118) Dustball Str./10 >170t (34) >290t (58) >610t (122) >1,060t (212) >1,675t (335) Dustball Strength >520t (104) >915t (183) >2,130t (426) >3,820t (764) >6,420t (1284) Stony Strength >2,955t (591) >4,200t (840) >8,200t (1640) >13,140t (2628) >22,965t (4593) Iron-Nickel Str. >6,965t (1394) >11,490t (2298) >25,585t (5117) >40,745t (8149) >64,710t (12943) Introduction Deflection: 1. Procedure 2. Impactors 3. Protection Asteroid Capture 9-12 May 2011 7Joan Pau Sanchez Table 3: Largest mass returned to Earth - parenthesis: fraction returned mass compared with the initial wet mass of the spacecraft  How much material could a 5000 kg low thrust spacecraft transport back to Earth?

9. Thank you! Contact email: jpau.sanchez@strath.ac.uk